Computer hard drives store data by affecting the magnetic field of memory cells on a hard drive disk. The stored data is read by passing a read head sensor above a memory cell to respond to, and thus detect, the orientation of the magnetic field in the memory cell. The smaller the memory cells on the hard drive disk, the more densely they can be packed, increasing the density of data storage possible on a hard drive disk.
However, as magnetic media recording density continues to increase, it is necessary for reader sensor geometry to diminish commensurately. As reader sensors become smaller, reader sensor design specifications become more aggressive and the tolerances tighter than those of traditional designs.
Described herein are methods, mill masks and devices resulting therefrom that utilize a developable-soluble bottom anti-reflective coating during the manufacture of reader sensors with very little sensor-to-sensor variability.